The binary compound Ag2S is named silver sulfide.
In this compound, silver (Ag) and sulfur (S) combine to form a substance that consists of two silver atoms for every one sulfur atom. The name reflects the metals present and their oxidation states: silver has a +1 oxidation state in this compound, while sulfur has a -2 oxidation state. This combination results in a neutral compound overall. Silver sulfide is known for its black color and is often formed as a result of the tarnishing process on silver items.